Objectives Stubbies: precise introduction Design criteria Design and components Procedure to increase prosthetic height to the full length prosthesis Advantages and drawbacks of stubbies
Stubbies Stubby (adjective): short and thick The Stubbies are the short prosthesis that uses the rocker-bottom platform attached directly to the end of socket or the extension/pylon with foot attached directly to the end of the socket. Indication: bilateral Transfemoral amputation
Stubbies: Design criteria Bilateral amputees purely depend mostly upon the prosthesis for their basic ADLs, the socket should be comfortable, easy to don and off with proper suspension. Prosthesis should be light in weight yet robust. Upper extremity condition will very much affect the design of the prosthesis specially the socket and suspension type. Height of the stubbies prosthesis kept as short as seat height of standard chair measuring from ischial tuberosity to reduce energy intake of waking. Further, better shock absorbing material are required in the foot/pylon to control pulmonary exchange. Easy ground clearance is also important hence foot design and alignment are also required to be considered .
Stubbies: Design and components Prosthesis design: Exoskeleton or Endoskeleton Socket design: both Sub-ischial or Ischial –containment socket are feasible. Suspension type: Simple Suspension like Silesian Band (integrated for right and left side socket for simplicity) or other vacuum or mechanical if desired. Design of feet: Wooden Rocker pattern (used in exoskeleton design) or Prosthetic foot or TD units (used in endoskeleton design) Arc of wooden rocker pattern is determined by keeping anatomical hip joint as center. They gives better ground clearance during swing. While length of the wooden rocker depends upon the effective length (from heel to MT head) of the natural foot length of the patient. Initial length of prosthesis: height measured from the ischial tuberosity or Greater Trochanter to the floor should not be less than 18 inches ( i.e seat height of standard chair) Exoskeleton Stubbies with wooden rocker pattern
Suspension: mainly TES/ Silesian band/ hip joint and pelvic band Silesian band AK strap suspension: Jaipur foot technology
Stubbies management: step by step procedure till full length Prosthesis Basic requirements: Tilt table: for graded weight bearing Parallel bar Crutches and Canes Gradual increase in the height is done from minimum height of 18 inches (measured from Ischial seat) to the full length Prosthesis
Stubbies management: step by step procedure till full length Prosthesis In case where bilateral prosthetic feet are used instead of wooden rocker pattern, i nitially the feet are kept in reverse way, as most of the weight in the Stubbies passes through Ischial tuberocity, hence posterior falling tendency exist. When patient feel sufficiently balanced and has minimal or no backward falling tendancy , the feet therefore can be rotated to normal position Usually every three months to six months duration, the height of the prosthesis (pylon length) is increased by two to three inches.
Stubbies management: step by step procedure till full length Prosthesis The knee is included when seating on the w/c seat or opening a door-lock becomes problem Gradually the pre-dominant side provide with single/polycentric knee joint, while the non-dominant side provided with mostly weight activated knee/polycentric knee Bilateral weight activated Prosthetic knee are seldom given. Walking stick/elbow crutches required when walking on uneven or inclined terrain
Stubbies advantages and drawbacks Advantages Safety: mostly used by adult amputee than child Stability Decreased energy cost Upright posture Confidence ADL facility Preparing for full length prosthesis Drawbacks Increased intrathoracic pressure thereby increased altered pulmonary ventilation Body image loss Social stigma Surrounding modification required
Thank you! Reference: AAOS, Atlas of amputations and Limb Deficiencies, 3 rd edition